Manfred Scheer

Coordination Chemistry of Phosphorous Containing Compounds Angela Dann May 8, 2006

Research Interests  Supramolecular Arrays  Fullerene-like nanoballs  Heteronuclear clusters with main group metal incorporation  1-Dimensional and 2-Dimensional Polymers  Complexes Containing a Tungsten Phosphorous Triple Bond

Fullerene-like Nanoballs [Cp x Fe( η 5 -P 5 )] + Cu I X Cp x = η 5 -C 5 Me 5 , η 5 -C 5 Me 4 Et X = Br, Cl, I  Soluble nanoballs form along with insoluble 1-D and 2-D polymers  Contain 90 non-carbon atoms

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Reaction Conditions  Mixed solvent system: CH 3 CN and CH 2 Cl 2  Soluble product formed upon increasing dilution (15 mmol/L  7.5 mmol/L)  Negligible amount of polymer formed with dilution of 3.75 mmol/L  2:1 optimum stoichiometry of CuBr:[Cp x Fe( η 5 P 5 )] x = η 5 -C 5 Me 5 or η 5 -C 5 Me 4 Et

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Structural Analysis  Black crystals  Broad 31 P NMR chemical shifts at 66 and 68 ppm  X-ray diffraction – P atoms coordinate to Cu atoms on both sides of CuBr   Core symmetry is

D 5h

Ethyl groups attached to Cp decrease symmetry to

C s

X-ray Structure

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Heteronuclear Clusters Incorporating Main Group Elements  Elevated synthetic and applied potential  Increased stability upon addition of main group element  1 st example of electrophilic addition of a Cp*M 2+ unit to an Fe 2 Q face of a cluster M = Rh, Ir Q = S, Se, Te Journal of Cluster Science 2003 ,

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Reaction Scheme [Fe 3 ( μ 3 -Q)(CO) 9 ][NEt 4 ] 2 + [Cp*M(CH 3 CN) 3 ][CF 3 SO 3 ] 2 M = Rh, Ir Q = S, Se, Te Journal of Cluster Science 2003 ,

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Initial Attempts  Attachment at edge or corner rather than at the Fe 2 Q face Journal of Cluster Science 2003 ,

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Addition to the Fe 2 Q Face  Two possible reaction pathways  

Closo

structure with a μ 3 -Q ligand – 60e Butterfly-shaped structure with a μ 4 -Q ligand – 62e  M = Rh – butterfly-shaped structure only  M = Ir – major product with butterfly-shaped structure, minor product with

closo

structure Journal of Cluster Science 2003 ,

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Reaction Pathways for M = Rh, Ir Journal of Cluster Science 2003 ,

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Structural Analysis  Black crystals  Soluble in toluene, CH 2 Cl 2 , and THF  IR – when Q = Se, peaks shifted to higher frequencies than for Q = Te  Mass spectra – characteristic fragments along with sequential loss of CO units Journal of Cluster Science 2003 ,

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CO Flexibility Examined by IR  In hexane – group of peaks between 2060 and 1900 cm -1 indicates terminal CO groups  One signal for the CO groups in 13 C NMR suggests high flexibility in solution  In Nujol – peaks below 1900 cm -1 indicate semi-bridging CO groups  Confirmed by X-ray diffraction Journal of Cluster Science 2003 ,

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X-ray Diffraction Studies Journal of Cluster Science 2003 ,

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X-ray Diffraction Studies Journal of Cluster Science 2003 ,

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Electrophilic Attack by REX 2  Incorporation of group 15 elements  E = As, Sb  Variations of R-group to create stabilized functionalized clusters  [Fe 3 ( μ 3 -Q)(CO) 9 ]K 2 used rather than [Fe 3 ( μ 3 Q)(CO) 9 ][NEt 4 ] 2 to produce pure products Dalton Trans. 2003 , 581

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Reaction Scheme Dalton Trans. 2003 , 581

Structural Analysis  X-ray diffraction –

nido

clusters  Square FeEFeQ unit capped by Fe fragment E = As, Sb Q = Se, Te  Only 1:1 stoichiometry gives desired product Dalton Trans. 2003 , 581

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1-D and 2-D Polymers  1-dimensional linear polymer forms immediately in CH 3 CN Chem. Eur. J. 2005 ,

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Structural Analysis  Red crystalline solid  Air and light sensitive  Very insoluble  IR – stretching frequencies indicate terminal CO groups  X-ray – small differences in ligand orientation Chem. Eur. J. 2005 ,

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X-ray Diffraction Chem. Eur. J. 2005 ,

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X-ray Diffraction of Polymer Backbone Chem. Eur. J. 2005 ,

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31 P MAS-NMR Spectra (X = Cl) Chem. Eur. J. 2005 ,

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31 P MAS-NMR Spectra (X = I) Chem. Eur. J. 2005 ,

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31 P MAS-NMR Spectral Analysis  X = Br, Cl – two multiplets separated by about 150 ppm  Homonuclear 1

J

( 31 P, 31 P) spin-spin interactions  Heteronuclear 1

J

( 63/65 Cu, 31 P) interactions  X = I – broad signal  Result of differences in orientation of Cp and CO ligands Chem. Eur. J. 2005 ,

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Cp and CO Ligand Orientations Chem. Eur. J. 2005 ,

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Additional Reactions  Reactions with CuCl 2 attempted and CuBr 2 also  Red needle-like crystals  Yielded same products as CuCl and CuBr  Reduction of Cu II X occurs  Cu I X complexes obviously represent the thermodynamic minimum Chem. Eur. J. 2005 ,

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Preparation of Phosphido Complexes [(RO) 3 W ≡P  M(CO) 5 ] R =

t

Bu, 2,4,6-Me 2 C 6 H 3 M = Cr, W  Lone pair of electrons on P coordinated by M(CO) 5 to increase stability  Thermolysis reaction of [Cp*P{W(CO) 5 } 2 ]  C-H activation followed by loss of CO leads to reactive intermediate [Cp*(CO) 2 W ≡P  W(CO) 5 ] Chem. Eur. J. 2001 ,

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Trapping Reactions with Alkynes  In situ generation of reactive intermediate and reaction with alkynes Chem. Eur. J. 2001 ,

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Structural Analysis  Black (4, 5), yellow (6), and red (7) crystalline solids  IR – stretching frequencies of terminal CO groups  31 P{ 1 H} NMR and X-ray diffraction studies Chem. Eur. J. 2001 ,

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31 P{ 1 H} NMR and X-ray Diffraction of Complex 4  Two singlets correspond to chemically non equivalent P atoms not coupled through W atom  Two 183 W satellites per singlet  Larger 1

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( 183 W, 31 P) value corresponds to bonding of P to W(CO) 5 Chem. Eur. J. 2001 ,

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31 P{ 1 H} NMR and X-ray Diffraction of Complex 5  Two doublets correspond to chemically non equivalent P atoms  1

J

( 31 P, 31 P) = 407 Hz  P-P multiple bond  No coupling of P atoms to W atoms Chem. Eur. J. 2001 ,

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 31 P{ 1 H} NMR and X-ray Diffraction of Complexes 6 and 7 Complex 6 – singlet with two 183 W satellites  Larger 1

J

( 183 W, 31 P) value corresponds to bonding of P to W(CO) 5  Complex 7 – singlet with one 183 W satellite Chem. Eur. J. 2001 ,

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Reaction Pathway  Thermolysis of [Cp*P{W(CO) 5 } 2 ] leads to:  Cp* migration  C-H activation  CO elimination  [2+2] cycloadditions with an alkyne  Stabilization of the [WPC 2 ] ring - Reaction with W-CO unit (complex 6) - Reaction with 2 nd unit of the intermediate (complex 4) Chem. Eur. J. 2001 ,

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